Division of the Generative Nucleus in Pines . . 215 
that in both instances two generative nuclei have been 
formed. 
When Professor Atkinson mentioned the pines as a favour- 
able subject for investigation, he referred to the then recent 
discoveries of Ikeno, Hirase, and Webber, and remarked that 
it would be most interesting to determine whether any sug- 
gestions or remnants of a cilia-forming body (called blepharo- 
plast by Webber in Z amici) still persist in the Conifers. Some- 
what later, after the present research was begun, MacMillan 
(’98) pointed out the desirability of such a study both in 
Coniferae and Gnetales. I have seen no indication in con- 
nexion with the formation of the sperm-nuclei in Pinus of 
a structure which might be regarded as a reduced blephar- 
oplast or as suggestive of a cilia-forming body of any sort. 
Inasmuch as spermatozoids do not exist here, such an organ, 
if present, must be functionless. But the cytoplasmic radi- 
ations which accompany the division, in its early stages, of 
the generative nucleus (Figs. 25 and 36), seem to differ in 
degree only from those found by Webber (’97, 1) in the 
generative cell of Zamia> as shown in his Figs. 3 and 5 ; and 
the question may be raised whether in this cytoplasmic figure 
we may not have still persisting in the cell the last vestiges 
of such an organ as that described by Webber. Neither has 
anything been observed throughout this study to indicate 
that the sperm-nuclei of Pinus ever assume the spiral or 
reniform shape, suggestive of spermatozoids, which has been 
described by recent writers 1 for the sperm-nuclei in various 
Phanerogams. The nuclei early become spherical or elliptical 
in outline, depending on the breadth of the pollen-tube, and 
remain so during their entire later history. 
Summary. 
1. The structure of the pollen-grain agrees fully with 
that described by Strasburger (’92). 
2. Pollination takes place in the neighbourhood of Cornell 
1 Golinski (’98) in certain grasses, Nawaschin (’99), Guignard (’99) and Sargant 
(’99) in Liliuni) Merrell (’00) in Silphum, and Thomas (’00) in Caltha. 
